textproduct: Quad Cities

KEY MESSAGES

- Warmer than normal temperatures will continue the remainder of the week and into next week.

- Rain chances will be on a slow increase through early next week. While there may be periods or areas that have better rain chances, overall areal coverage on average will likely be 15-30 percent.

SHORT TERM /THROUGH THURSDAY/

Issued at 246 PM CDT Wed Sep 17 2025

Weak upper level disturbance initiated 20-30 percent coverage of showers and some storms across the northwest parts of the area late this morning that have persisted into mid-afternoon. These showers and few storms will persist into the late afternoon and evening. With the exception of a few areas, coverage on any rain will continue to be isolated to scattered (15-30 percent).

Tonight into Thursday, the upper level trof in the Plains will slowly move east. Water vapor and model output shows three or four upper level disturbances will rotate around the base of the trof and move through eastern Iowa through late Thursday afternoon. Each one will either initiate 15-30 percent coverage of showers and some storms (with small areas of higher pops) or help maintain them. Each round will run into drier air along and east of the Mississippi which will cause each round to dissipate upon reaching the river.

Sadly, most areas will remain dry for the next 36 hours. Those areas that do see rain will be the lucky ones.

LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/

Issued at 246 PM CDT Wed Sep 17 2025

Thursday night through Tuesday night Assessment...High (>80%) confidence on above normal temperatures. Low (20-30%) confidence on rain chances

The strong upper level ridge that has been over the area will slowly shift east of the area and allow the upper level trof in the Plains to move closer to the area.

The models show many upper level disturbances will rotate through the area that will have the potential to bring some rain to the area. Yesterday the probabilities of seeing 0.01 inches of rain through the weekend was near 100 percent for the entire area. However, the stretch of dry weather that we have experienced has likely resulted in an increase to the negative feedbacks which will lower the overall rain chances.

As a result, the model consensus is generally depicting rain chances at 20-35 percent each period through Tuesday night with two exceptions; Thursday night into Friday and Sunday night. These time frames the models depict stronger upper level disturbances which support a better signal for rain potential; 40-60 percent. However, if the negative feedbacks are on the increase, the chances for rain in these time frames have the potential to decrease as we get closer to them.

Wednesday Assessment...medium to high (60-80%) confidence on dry conditions

The global models are indicating a pattern change to the flow aloft developing around the middle of next week. As a result, the models are struggling on how to handle upper level energy approaching the area. The models to varying degrees are developing a cut off upper low but disagree on where the cut off develops or eventually moves.

Yesterday, the ECMWF dropped the cut-off low to the WI/IL border suggesting cooler temperatures and a rain potential. Today it has no cut-off low. The UKMET has no cut-off low while the GFS/CMC take the upper low over the northern Great Lakes into southeast Canada. The ICON model kept the cut-off low well north of the area yesterday and today it brings it across the area. Since model predictability naturally lowers during a pattern change, run-to-run trends of the models will be important as to which scenario eventually plays out.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 606 PM CDT Wed Sep 17 2025

Rain showers and thunderstorms continue over central Iowa, but continue to fall apart as they slowly move towards eastern Iowa this evening. An outflow boundary has temporarily moved to near CID, resulting in northwest winds gusting to 20 kts, but this will once again revert to light and variable winds overnight, at all sites, and also through most of Thursday. Though an isolated shower or storm could spread into areas west of DBQ to CID, those chances appear very low and unlikely to impact any TAF sites through Thursday afternoon. Trends will be monitored from the central Iowa activity, but with dry air over eastern Iowa, we continue to offer a VFR condition forecast.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.